1. Field of the Invention
The invention relates to a medium transporting apparatus for use in an image forming apparatus such as a printer, a copier, a facsimile machine and a multifunction printer (MFP), and also relates to the image forming apparatus having the medium transporting apparatus.
2. Description of the Related Art
A conventional image forming apparatus such as a printer includes a sheet feeding mechanism, an image-forming unit, a transfer unit and a fixing unit. The image-forming unit forms a toner image in accordance with print data. The transfer unit transfers the toner image to a sheet fed by the sheet feeding mechanism. The sheet with the toner image thereon is advanced to the fixing unit where the toner image is fused into a permanent image on the sheet, and is then discharged from the image forming apparatus.
The sheet feeding mechanism includes a feed roller, a separator and a pressure member. The feed roller feeds a sheet accommodated in a sheet cassette. The separator is provided in opposition to the feed roller. The pressure member urges the separator against the feed roller. A guide member is disposed downstream of the feed roller and guides the sheet fed by the feed roller in a predetermined direction. A pair of transport rollers is provided further downstream of the guide member and transports the sheet guided by the guide member.
When a feed motor rotates the feed roller at a predetermined speed, a sheet is picked up from a sheet loading plate in the sheet cassette and is advanced to a nip portion formed between the feed roller and the separator. If a plurality of sheets are picked up from the sheet loading plate at the same time, they are separated one-by-one at the nip portion. Then, the sheet is advanced to the transport rollers along the guide member. Japanese Patent Laid-Open No. 10-171199 discloses one such sheet feeding mechanism. With the sheet feeding mechanism disclosed in the patent document, the guide member is U-shaped so as to reverse the direction of sheet transport, thereby miniaturizing the image forming apparatus.
In the aforementioned mechanism, however, since a front end of the sheet fed by the feed roller abuts a surface of the guide member at a steep angle, a large frictional force acts on the front end of the sheet. Therefore, the sheet is unable to slide smoothly on the surface of the guide member. This might cause adverse effects on the transport of the sheet.